Autofluorescence spectral analysis for detecting urinary stone composition in emulated intraoperative ambient

Multiwavelength Fluorescence and Diffuse Reflectance Spectroscopy for an In Situ Analysis of Kidney Stones

“…Namely, oxidation and an accumulation of uric acid and other specific molecules may result in higher fluorescence and shifted emission. Similar explanations are presented in a recent paper on stones autofluorescence [26], where it is stated that "a plausible explanation is that stones with different inorganic substances contain distinct classes of matrix proteins, the latter of which, likely played a major role in shaping the spectra as we already show that pure inorganic substances exhibit very weak autofluorescence". Some additional considerations regarding the fluorescence of organic components within stones can be found in [25], where discrimination between organic and inorganic fractions was performed based on non-linear microscopy.…”

“…Previous studies, such as the one by Xing et al, have utilized EEMs for two types of classification: distinguishing calcium stones (calcium oxalate monohydrate and dihydrate) from other types of stones (urate and struvite) [26]. The presented study demonstrated classification accuracies exceeding 90% for the multi-class task.…”

“…The presented study demonstrated classification accuracies exceeding 90% for the multi-class task. The method proposed here differs from that in [26], where binary classification based solely on the EEMs of stones was performed. In contrast, our model is multi-class and achieves high accuracy by combining two methods of optical spectroscopy.…”

“…The Implemented scheme requires only minor modifications for measurements using a single fiber, meaning it can be adapted for equipment used by surgeons during endoscopic operations. Since the excitation wavelength range (260-480 nm) and the fluorescence spectra registration range (above 500 nm) do not overlap, a simple setup using a dichroic mirror with a cutoff wavelength around 500 nm is sufficient along the lines of Xing et al's study [26]. Diffuse reflectance spectra in the 450-600 nm range can also be measured using a single fiber with endoscope illumination.…”

“…Notably, uric acid stones have been found to exhibit high fluorescence intensity when exposed to green light compared to other types of stones [25]. Recent research has also demonstrated the ability of fluorescence spectroscopy to distinguish between calcium-containing stones and those without calcium with high accuracy [26]. Furthermore, the spectral analysis of diffusely scattered light by a stone can provide information about its scattering properties which relate to optical heterogeneities within the stone and absorbing properties associated with the concentration of various chromophores.…”